package day18;

import java.util.Scanner;

public class demo1 {
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        int n=in.nextInt();
        for(int i=0;i<n;i++){
            int x=in.nextInt();
            int []ch=new int[26];
            for(int j=0;j<x;j++){
               int a=in.next().charAt(0)-'a';
                ch[a]++;
            }
            int count=0;
            for(int f=0;f< ch.length;f++){
                if(ch[f]%2!=0){
                    count++;
                }
            }
            if(count>1) System.out.println("No");
            else System.out.println("Yes");
        }
    }
}
